Throttle valve mechanisms

ABSTRACT

In a throttle valve mechanism having a housing in which a pendulum depending from the housing is universally swingable around a geometrical axis of the housing and in which a plurality of throttle valves are arranged and each have one displaceable throttling valve member for varying the throttling effect of the respective throttle valve, the throttling valve member is displaceable by means of an actuating piston movable in an actuating cylinder connected with a control cylinder in which a control piston is displaceable, a liquid body being enclosed and filling the space between the actuating piston and the control piston, the control pistons for the throttle valves being spaced around said geometrical axis adjacent the upper end of the pendulum which has means engaging the control pistons for displacing them in the control cylinders as a result of swinging movement of the pendulum, the effective cross-sectional area of the actuating pistons being smaller than that of the control pistons so that the actuating pistons will be displaced a greater distance than the distance through which the control pistons are displaced by the pendulum.

[451 Aug. 28, 1973 United States Patent [191 Gustafsson 1 THROTTLE VALVEMECHANISMS ABSTRACT In a throttle valve mechanism having a housing inwhich a pendulum depending from the housing is universally swingablearound a geometrical axis of the housing and in which a plurality ofthrottle valves are arranged and each have one displaceable throttlingvalve member for varying the throttling effect of the respectivethrottle valve, the throttling valve member is displaceable by means ofan actuating piston movable in an actuating cylinder connected with acontrol cylinder in which a control piston is displaceable, a liquidbody being enclosed and filling the space between the actuating pistonand the control piston, the control pistons for the throttle valvesbeing spaced around said geometrical axis adjacent the upper end of thependulum which has means engaging the control pistons for displacingthem in the control cylinders as a result of swinging movement of thependulum, the effective cross-sectional area of the actuating pistonsbeing smaller than that of the control pistons so that the actu atingpistons will be displaced a greater distance than the distance throughwhich the control pistons are displaced by the pendulum.

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SHEET 2 0F 4 Ill 7 2 THROTTLE VALVE MECHANISMS This. invention relatesto a throttle valve mechanism having a housing in which a pendulumdepending from the housing is mounted for universal swinging movementaround a centre on a geometrical axis of the housing and in which aplurality of throttle valves are arranged and each have one displaceablethrottling valve member which is adjustable by means of the penduluminto different throttling states in response to the position taken bythe pendulum in relation to the geometrical axis.

Such throttle valve mechanisms are used in devices for lifting andlowering heavy objects, such as transport containers, to controlpressure fluid driven lifting elements placed around and connected tothe object, so that these devices will lift and lower the object to auniform extent and the object is not subjected to any precarious tiltingmovement when lifted or lowered. The throttle valve mechanism can beplaced on the container with the above mentioned geometrical axis invertical position. If the object during lifting or lowering begins totilt because some lifting element operates more rapidlyor more slowlythan the other lifting elements the pendulum will swing away from saidgeometrical axis, thereby actuating the throttle valves in such a waythat the speeds of the lifting or'lowering movements of the liftingelements are altered to compensate for the upsetting tendency. i j

. Prior art throttle valve mechanisms of the type outlined in theforegoing suffer from the drawback that a relatively large swingingamplitude of the pendulum and thus a heavy obliquity of the object isrequired before the throttle valve mechanism is able to compensate forthe upsetting tendency of the object to an appreciable extent, Wherevery large and very heavy objects are concerned it is imperative,however, that a throttle valve mechanism of the type outlined in theforegoing already at very small swinging amplitudes of the pendulumprovides a large compensation of the upsetting tendency of the object.

The present invention has for its object to provide a throttle valvemechanism of the type outlined in the foregoing which is very sensitiveto positional changes and thus realizes a large variation of thethrottling effects of the throttle valves at. a, small change inposition of the pendulum.

According to the invention, the valve member of each throttle'valve hasan actuating piston which is sealingly displaceable in a cylinder anddefines a liquid filled chamber which has a cylinder portion of largercross sectional area than thatof the cylinder of the actuating piston,21 control piston beingsealingly displaceable in said cylinder portionof the liquid filled chamher. and the actuating pistons of the'throttlevalves are arranged in the throttle valve mechanism housing spacedaround the geometrical axis of saidhousing and tion;

FIG. 2 shows a lifting element used in the lifting device shown in FIG.1, a reversing valve mechanism, the throttle valve mechanism accordingto the invention, a control valve mechanism, and a pressure fluid sourcewith appertaining pressurefluid lines;

FIG. 3 shows a partial side view and partial sectional view of athrottle valve mechanism according to the invention with the lowerportion of the pendulum cut away;

FIG. 4 shows a hydraulic circuit diagram.

FIG. 1 shows a parallel-epipedical transport container l which is raisedfrom the ground 2 by means of four hydraulic lifting elements 3. Thelifting elements 3 each have one bracket 4. These brackets are in aknown manner detachably hooked to the side walls of the transportcontainer 1 in the vicinity of each container end wall. Secured to oneof the brackets 4 is a reversing valve mechanism 5 and a throttle valvemechanism 6. As will be more fully described in the following, thethrottle valve mechanism 6 has a housing in which a pendulum 7 dependingfrom the housing is universally swingable around a geometrical axis ofthe housing. The housing is so-fastened to the bracket 4 that saidgeometrical axis of the housing, when the bracket is hooked to thetransport container 1, is parallel with the vertical centre axis of thecontainer 1.

As will appear from FIG; 2 each lifting element 3 is a double-actingcylinder and piston assembly the piston rod 8 of which rests on theground 2 and the cylinder 9 of which is fixed to the bracket 4 shown inFIG. 1 but not in FIG. 2. The upper and lower ends of the cylinder 9 areconnected via lines'l0 and 11 to the reversing valve mechanism 5.Separate lines l0 and 11 pass from the cylinder 9 of each liftingelement 3 to the valve mechanism 5. Four lines 12 lead from the valvemechanism 5 to four throttle valves in the throttle valve mech anism6.The valve mechanisms 5 and 6 could be built together in a single housingso that the lines 12 may be internal passages in the housing. A pressurefluid source in the form of a pump 14 driven by a motor 13 suppliespressure fluid from a receptacle 15 to a control valve 16. Two lines 17and 18 connect the valve 16 to the reversing valve mechanism 5. Thevalve 16 can be set in a known manner into a position in which pressurefluid from the pump 14 flows through the line 17 to the valve mechanism5 while the line 18 is in communication with the supply receptacle 15,and into another position in which pressure fluid flows from the pump 14through the line 18 to the reversing valve mechanism 5 while the line 17is in communication with the supply receptacle 15. Besides, the throttlevalve mechanism 6 is connected via a line 19 to the supply receptacle15.

The throttle valve mechanism 6 is shown in detail in FIG. 3. It has asubstantially cylindrical housing 2 0 which is fastened by fasteningdevices (not shown) in such a way to the bracket 4 (shown in FIG. 1)that the geometrical centre axis 21 of the housing is parallel with thecentral height axis of the transport container 1. The housing comprisesa number of throttle valves corresponding to the number of liftingelements :3 (FIG. 1), Le. in the embodiment chosen four throttle valveswhich are spaced around the centre axis 21 in such a way that thethrottle valves in horizontal projection are at the corners of aquadrangle. The housing 20 shall be fastened to the bracket 4 (FIG. 1)in such a way that said quadrangle is oriented in the same way as' thehorizontal quadrangle at the corners of which the four lifting elements3 are placed.

The four throttle valves in the housing are identical, and FIG. 3 showsone of the throttle valves in axial section and partly in sideelevation. This throttle valve will now be described, and thedescription applies to all four throttle valves. In the embodimentchosen, the throttle valve is of the needle valve type. Thus it has aconical valve member 22 which is integral with an actuating piston 23which is sealingly displaceable in a cylinder 24 formed by a bore in thehousing 20 and having its axis parallel with the axis 21 of the housing20. The lower end of the actuating piston 23 projects into a cylinder 25formed by a bore in the housing 20 and coaxial with the cylinder 24 buthaving a considerably larger diameter than said cylinder. The lower endof the actuating piston 23 has a pin 26 which is guided in a bore formedin a control piston 27 which is sealingly displaceable in the cylinder25. The pistons 23 and 27 define between them in the cylinder 25 achamber 28 which is entirely filled with liquid. The filling of liquidinto the chamber 28 can take place through a fill passage 30 which isnormally closed by means of a screw plug 29.

The lower ends of the control pistons 27 of the four throttle valvesproject from a lower end wall of the housing 20 and engage a disk 31 onthe upper end of the pendulum 7. Beneath the disk 31 the pendulum has aspherical portion 32 by means of which the pendulum is mounted foruniversal swinging movement in a spherical bushing in a cover 33 screwedinto the lower end of the housing 20. The pendulum 7 is so mounted thatit can swing around a centre on the centre axis 21.

The conical valve member 22 cooperates with a valve seat at the lowerend of a piston 34 which is movable in the cylinder 24. A spring 36interposed between the upper end of the piston 34 and a set screw tendsto move the piston 34 downwards to urge the seat of the piston againstthe valve member 22. The piston 34 has an annular groove 37 which viapassages 38 in the piston is in communication with the valve seat of thepiston. Within the region of the groove 37 the housing 20 has aconnecting bore 39 for one of the lines 12 (FIG. 2) from the reversingvalve mechanism 5 so that liquid supplied through this line and beingunder a given pressure can flow into the groove 37 and pass through thepassages 38 to the valve seat. Within the region of the conical valvemember 22 the cylinder 24 is intersected by a bore 40 which is radialwith respect to the cylindrical housing 20 and is in communication witha connecting bore 41 for the line 19 (FIG. 2) leading to supplyreceptacle 15. There is one radial bore 40 for each of the four throttlevalves and these bores are in communication with each other at thecentre of the housing. Only one of the bores 40 need have a connectingbore 41 for leading off liquid from all four throttle valves to thesupply receptacle 15.

FIG. 4 shows a complete circuit diagram of the hydraulic circuits. Thecontrol valve 16 is shown in FIG. 4 in the form of a slide valve thepiston of which is set in FIG. 4 into a position to connect the line 17to the pump 14 and the line 18 to the supply receptacle 15. This is theposition of the valve 16 in which it causes the lifting units 3 to liftthe container 1. The reversing valve mechanism 5 is shown in FIG. 4 inthe form of a slide-type valve member 42 which is movable in acylinr derand has a plurality of annular grooves for establishing variousconnections between the lines opening into the cylinder wall of thevalve mechanism, said slidetype'valve member being settable into twoextreme positions in the cylinder with the aid of pressure fluid fromthe lines 17 and 18, respectively, which lines are each connected to oneend of the cylinder. Since the line 17 in FIG. 4 is connected to thepump 14, the valve member 42 in FIG. 4 is moved into its left endposition so that pressure fluid from the line.l7 according to the lineconnections illustrated is supplied to the upper end of the cylinders ofthe lifting units 3, whereby said lifting units 3 will lift thecontainer 1. This will force out pressure fluid from the lower end ofthe cylinders of the lifting units 3, said pressure fluid flowingthrough the lines 11 to the reversing valve mechanism 5 and through thelines 12 to the throttle valves 22, 34. It will appear from the circuitdiagram in FIG. 4 that the lines 1 l of the lifting units 3 areconnected by means of the reversing valve mechanism 5 individually tothe respective throttle valves 22, 34 which are diagonally opposed inhorizontal projection.

The pressure fluid arriving from the respective lifting unit 3 duringthe lifting operation and flowing through a line 11 and a line 12 to therespective throttle valve 22, 34 enters the throttle valve housing 20through a connecting bore 39 (FIG. 3) and penetrates from the groove 24of the piston 34 through the passage 38 to the valve seat. The pressurefluid is under a certain pressure and by reason of the describedconstruction of the piston 34 is capable of raising the piston 34slightly from the valve member 22 against the action of the spring 36.The pressure fluid thus flows, while beingv throttled, through the valveseat around the valve member 22 to the passage 40 and through theconnecting bore 41 and the line 19 connected therewith to the supplyreceptacle 15. The throttling effect in the valve seat has a brakingeffect on the lifting movement of the respective lifting unit. If forinstance the left lifting unit 3 which is the upper one in FIG. 4 tendsto lift more rapidly than the other lifting units 3 the height axis ofthe container 1 and thus the axis 21 of the throttle valve housing willtake an oblique position so that the axis of the vertically dependingpendulum 7 is set in an oblique position to the axis 21 in such adirection that the disk 31 of the pendulum 7 urges the control piston27.0f the throttle valve shown to the lower right in FIG. 4 some furtherdistance into the cylinder 25, the pressure fluid in the chamber 28urging the piston 23 to a considerably higher level in the cylinder 24due to the difference in size between the effective cross sectionalareas of the pistons 27 and 23, whereby the valve member 22 is movedtowards the seat in the piston 34 and heavily increases the. throttlingeffect in the valve seat, thereby increasing the braking of the liftingmovement of the lifting unit 3 positioned to the upper left with regardto the lifting movements of the other lifting units. As a consequence,the container 1 will be rapidly straightened so that its height axis isagain vertically directed and upsetting of the container is avoided.

For a lowering of the container 1 by means of the lifting units 3 thecontrol valve 16 is so adjusted that the line 18 will be put incommunication with the pump 14 and the line 17 will be put incommunication with the supply receptacle 15. As a result the reversingvalve piston 42 will be set into its right end position so that pressurefluid from the line 18 will be supplied to the lower end of thecylinders of the lifting units 3 through the lines 11 and the upper endsof the cylinders of said lifting units 3 will each be connected throughthe lines to one of the throttle valves 22, 34. In this case, however,the reversing valve mechanism 5 has connected the different liftingunits to the respective throttle valves 22, 34, i.e. in such a way thatfor instance the upper left lifting unit 3 in FIG. 4 is connected to theupper left throttle valve. If for instance the upper left lifting unit 3in FIG. 4 tends to lower the container 1 more rapidly than the otherlifting units the container and thus the centre axis 21 of the throttlevalve housing will be put in an oblique position so that the disk 31 ofthe vertically depending pendulum 7 will urge the control piston 27of-the upper left throttle valve in FIG. 4 a small distance inwardly inthe cylinder 25, whereby the piston 23 will be urged a considerablylarger distance upwardly in the cylinder 24. As a result, the throttlingeffect in the throttle valve in question will be heavily increased sothat the lowering movement of the upper left lifting unit in FIG. 4 willbe braked in relation to the lowering movement of the other liftingunits to readjust the height axis of the container into a purelyvertical position. 7

IS. a v

1. A throttle valve mechanism, comprising a housing, a pendulumdepending from said housing, means mounting the upperend of saidpendulum in said'housing for universal swinging movement around a centreon a geometrical axis of said housing, a plurality of What I claimanddesire to secure by Letters Patent throttle valves in said housing,inlet means and outlet means of said valves in said housing, said valveseach comprising a throttling valve member displaceable for varying thethrottling effect of said valve, an actuating piston connected to saidthrottling valve member for displacing said member, an actuatingcylinder in said housing in which said actuating piston is sealinglydisplaceable, a control cylinder in said housing, a control pistonsealingly displaceable in said control cylinder, said actuating cylinderand said actuating piston having a smaller effective cross-sectionalarea than said control cylinder and said control piston, and saidactuating cylinder and said control cylinder being interconnected, aliquid body being enclosed and filling the space between said actuatingand control pistons in said actuating and control cylinders, saidcontrol pistons of said throttle valves being spaced around saidgeometrical axis of said housing adjacent the upper end of saidpendulum, and means on the upper end of said pendulum engaging saidcontrol pistons for displacing said control pistons in said controlcylinders as a result of swinging movement of said pendulum.

2. A throttle valve mechanism according to claim 1 in which saidthrottle valves are needle valves.

3. A throttle va'lvemechanism according to claim 1 in which saidthrottling'valve member, said actuating piston and said control pistonof each throttle valve are coaxially arranged in said housing on an axisparallel to said geometrical axis of said housing.

1. A throttle valve mechanism, comprising a housing, a pendulumdepending from said housing, means mounting the upper end of saidpendulum in said housing for universal swinging movement around a centreon a geometrical axis of said housing, a plurality of throttle valves insaid housing, inlet means and outlet means of said valves in saidhousing, said valves each comprising a throttling valve memberdisplaceable for varying the throttling effect of said valve, anactuating piston connected to said throttling valve member fordisplacing said member, an actuating cylinder in said housing in whichsaid actuating piston is sealingly displaceable, a control cylinder insaid housing, a control piston sealingly displaceable in said controlcylinder, said actuating cylinder and said actuating piston having asmaller effective cross-sectional area than said control cylinder andsaid control piston, and said actuating cylinder and said controlcylinder being interconnected, a liquid body being enclosed and fillingthe space between said actuating and control pistons in said actuatingand control cylinders, said control pistons of said throttle valvesbeing spaced around said geometrical axis of said housing adjacent theupper end of said pendulum, and means on the upper end of said pendulumengaging said control pistons for displacing said control pistons insaid control cylinders as a result of swinging movement of saidpendulum.
 2. A throttle valve mechanism according to claim 1 in whichsaid throttle valves are needle valves.
 3. A throttle valve mechanismaccording to claim 1 in which said throttling valve member, saidactuating piston and said control piston of each throttle valve arecoaxially arranged in said housing on an axis parallel to saidgeometrical axis of said housing.